Variability analysis of vibrational responses in a passenger car considering uncertainties of elastomers

Passenger Car has many elastomeric joints in order to reduce vibration transmission from source to cabin structure through joints. In design stage, the dynamic characteristics of the elastomeric joints are optimally determined to satisfy design goals for interior noise and vibration. However, the material properties of the elastomeric joints have large variation due to productional variability. In addition, operational conditions, for example, environmental temperature vary according to the locatons of cities. As result, vibrational comfort of a passenger car shows large variation. In this paper, the amount of vibration fluctuation due to uncertain elastomeric joint parameters is estimated by using a statistical approach. First, the dynamic characteristics of elastomers are described by the fractional derivative model. The uncertainties of the fractional-derivative-model parameters of the elastomers are characterized using a statistical calibration approach based on specimen test data. Then, a finite element model for the elastomers and structure of a passenger car are contructed in order to calculate vibrational response. To estimate the variability of the vibrational response due to the uncertainties of the elastomers, the uncertainty propagation analysis is carried out using the eigenvector dimension reduction (EDR) method. Operational condition such as temperature is also included in the variability analysis. The performance of the EDR method is assessed by comparing the estimated response distribution with that of Monte Carlo simulation method in a simplified structure. The variability analysis results show that the vibrational response variation due to the uncertainties of the elastomers can be efficiently predicted using the proposed method. The proposed variability analysis procedure will be a good tool in design stage for comport quality control of passenger cars.